Computed Tomography (CT) has had an enormous impact on medicine since its introduction, and many physicians consider CT (along with MRI) to be the most important recent technological innovation in medicine. Further technical improvements would have important clinical benefit, but the system design in use in current CT systems, even the most advanced clinical scanners, is not able to achieve the combination of capabilities that is needed. We recently proposed a radically different CT system design, Inverse Geometry CT (IGCT) that promises to deliver wide volumetric coverage in a single rapid scan with no "cone-beam" artifacts, high spatial and temporal resolution, improved dose efficiency, and reduced radiation dose to the patient. Our preliminary results provide strong evidence that these goals can be achieved The goal of this proposal is to perform research leading to and including designing and constructing a fullscale prototype IGCT system capable of animal and human scanning, to quantitate its performance, and to perform pilot in-vivo studies. The research involves a collaboration between Stanford University and GE's Global Research (GEGR) Center, building on the pioneering work on IGCT performed at Stanford and the important advances and unique capabilities of the team at GEGR. The groups will collaboratively optimize the system design, perfect calibration and reconstruction algorithms, and perform detailed evaluations. The Stanford group, led by the PI, will be responsible for defining the clinical requirements and performing the animal and human studies. The GEGR group, led by Bruno De Man, will be responsible for detailed system design and construction. While the significance and potential impact of this research are very large, the scope and risk preclude it from being performed by industry alone and public support is required. At the same time, the impact of the requested budget is amplified by existing funding and ongoing research at both Stanford and GEGR, and by a commitment of 1$M from GE Healthcare to fund construction of the gantry based system. We believe that important research and clinical application would be possible with CT systems capable of much wider volumetric coverage in short scan times, requiring lower radiation dose than present systems, and delivering uncompromised image quality and temporal resolution. CT technology currently in use is not up to this task, and that a new approach is needed. We believe, and our preliminary studies show, that our IGCT approach will be able to open this new era in CT scanning.